Incorrect transform result for `/(?i:\u1C89)/`

[JLHwung]

Current output:

/(?i:\u1C89)/

Expected output:

/(?:[\u1C89\u1C8A])/

Context: The U+1C89 (CYRILLIC CAPITAL LETTER TJE) and U+1C8A (CYRILLIC SMALL LETTER TJE) are introduced in Unicode 16.0 released this year. According to UnicodeData.txt and SpecialCasing.txt they should be match by /\u1C89/i. However, because node.js 22 does not support them in toUpperCase, they are incorrectly categorized as unicode mappings:

regexpu-core/scripts/case-mappings.js

Lines 164 to 169 in f2f88e6

	if(
	// TODO: Make this not depend on the engine in which this build script
	// runs. (If V8 has a bug, then the generated data has the same bug.)
	!RegExp(String.fromCodePoint(from), 'i').test(String.fromCodePoint(to))
	) {
	extend(filteredMappings, from, to);

To address this, we can add UnicodeData.txt and SpecialCasing.txt to the node-unicode-data and replace the engine test by the result only derived from the latest UCD.